Oil and gas production in both conventional and unconventional low permeability reservoirs has been heavily relied on hydraulic fracturing technology in the last two decades. By utilizing excessive hydraulic pressure to crack the formation rock, artificially generated preferential flow paths from the wellbore to the formation could increase the contact area between well and reservoir by orders of magnitude. Consequently, flow of hydrocarbons can be significantly facilitated by highly permeable induced fractures. Proppants are used to keep the fracture walls apart to create a conductive path to the wellbore after pumping has stopped and the fracturing fluid has leaked off. Placing the suitable concentration and type of proppant in the fracture is critical to the success of a fracturing treatment. Factors affecting the fracture conductivity (a measurement of how a propped fracture is able to pass the produced fluids over the production life of the well) are proppant grain size distribution, proppant-pack permeability, physical properties of the proppant, and long-term degradation of the proppant. To open and propagate a hydraulic fracture, fluid pressure must overcome the in situ stresses. Proppants are injected with the fracturing fluid to prevent the potential closure. After the well is put on production, earth stress acts to close the induced fracture and confine the placed proppants (see FIG. 1). If the proppant strength is inadequate, the closure stress closes the fracture or crushes the proppant, which reduces the conductivity of the proppant pack. Thus, there is a need to produce strong expandable proppants that overcome current limitations.